800mpa-grade hot-rolled dual-phase steel sheet with excellent performance and its manufacturing method

Abstract

The invention provides a 800MPa grade hot-rolled dual phase steel plate with excellent performance and a manufacturing method thereof. The components of the steel plate include, by weight percentage,0.04-0.08% of C, 0-0.10% of Si, 1.6-2.0% of Mn, 0.20-0.40% of Als, 0.50-0.80% of Mo, 0.02-0.05% of Nb, 0.02-0.05% of Ti, P being less than 0.02%, and S being less than 0.005%, with the balance being Fe and inevitable impurities; and the manufacturing method includes smelting, continuous casting, heating, rolling and cooling. The intensity of the produced dual phase steel plate can reach more than800 MPa, and the ferrite content can reach 85-95%; and the steel plate has good intensity and elongation cooperation and excellent forming performance.

Description

technical field [0001] The invention belongs to the field of steel rolling, and in particular relates to an ultra-fine-grained ferrite and martensitic hot-rolled dual-phase steel plate with excellent 800MPa performance and a manufacturing method thereof. Background technique [0002] In recent years, with the rapid development of the automobile industry, the performance requirements of automobiles on steel materials have become more and more stringent, and there are more and more individualized requirements for automobile parts. In this form, the use of high-strength steel materials with outstanding performance characteristics and excellent comprehensive properties is one of the best choices for automobile manufacturers to achieve lightweight vehicles. [0003] The hot-rolled dual-phase steel composed of soft phase ferrite and hard phase martensite has attracted the attention of automobile manufacturers due to its remarkable individual performance characteristics and excelle...

AI Technical Summary

Problems solved by technology

But so far, the strength grades of hot-rolled dual-phase steel are mainly 540MPa and 600MPa, which can no longer meet the requirements of the development of lightweight automobiles for the improvement of steel strength. Therefore, the development of hot-rolled dual-phase steel with higher strength has become a current trend

[0004] "A dual-phase steel with a tensile strength of 715-795MPa and its manufacturing method" (publication number CN1793400A) discloses that the strength of the hot-rolled dual-phase steel plate reaches between 715MPa-795MPa, and the C content in the composition is relatively high, which is 0.13-0.17%. High C content deteriorates the weldability of the steel plate. At the same time, ultra-rapid cooling and extremely low-temperature coiling process are adopted after final rolling. The cooling process is complicated and difficult to control, and requires ultra-rapid cooling equipment and strong coiling capacity, which is difficult to achieve

[0005] "Ultra-fine-grained hot-rolled dual-phase steel with tensile strength above 750MPa and manufacturing method thereof" (publication number CN101880825A) discloses that the tensile strength of the steel sheet reaches above 750MPa, but the steel sheet contains a certain amount of Si element, which will deteriorate the surface of the steel sheet Quality, at the same time it adopts low temperature coiling process after rolling

[0006] "A Method for Manufacturing Hot-Rolled Dual-Phase Steel Sheet with Tensile Strength of 700MPa" (publication number CN101279330A) discloses that the tensile strength of the steel sheet reaches 700MPa, and the C-Si-Mn-Cr-Mo-Nb composition system is used in the composition, and the Si content Higher, reaching 0.50-0.70%, will deteriorate the surface quality of the steel plate

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